| 主权项 |
1. A power conversion apparatus for converting DC power, supplied from a first DC power supply having a first electrode and a second electrode, and from a second DC power supply having a first electrode connected to a second electrode of said first DC power supply and a second electrode, into AC power, and supplying the AC power to a load, said power conversion apparatus comprising:
a first main switch having a first end coupled to the first electrode of said first DC power supply, and a second end coupled to said load, a first main diode connected in parallel with said first main switch, so as to have a conducting direction opposite to the conducting direction of said first main switch, a first snubber capacitor connected in parallel with said first main switch and said first main diode, a first snubber diode connected in series with said first snubber capacitor and connected between said first snubber capacitor and the second end of said first main switch, so as to have a conducting direction identical to the conducting direction of said first main switch, a first auxiliary switch and a first auxiliary reactor connected between a connection node of said first DC power supply and said second DC power supply and a connection node of said first snubber capacitor and said first snubber diode, and connected in series with each other, a second main switch having a first end coupled to the second end of said first main switch and the second end coupled to the second electrode of said second DC power supply, provided so as to have a conducting direction identical to the conducting direction of said first main switch, a second main diode connected in parallel with said second main switch, so as to have a conducting direction opposite to the conducting direction of said second main switch, a second snubber capacitor connected in parallel with said second main switch and said second main diode, a second snubber diode connected in series with said second snubber capacitor, and connected between said second snubber capacitor and the first end of said second main switch, so as to have a conducting direction identical to the conducting direction of said second main switch, a second auxiliary switch and a second auxiliary reactor connected between a connection node of said first DC power supply and said second DC power supply and a connection node of said second snubber capacitor and said second snubber diode, and connected in series with each other, and a protection circuit for causing, when voltage applied to said first snubber capacitor becomes greater than or equal to a predetermined value or when voltage applied to said second snubber capacitor becomes greater than or equal to the predetermined value, a charging current formerly flowing from said first DC power supply and said second DC power supply to said first snubber capacitor or said second snubber capacitor to flow to another current path, said protection circuit including a first transformer and a second transformer, and a first clamp diode and a second clamp diode,
said first transformer including
a first primary winding connected between the second end of said first main switch and said load, anda first secondary winding connected between the first electrode of said first DC power supply and the second electrode of said first DC power supply, and magnetically coupled to said first primary winding,said second transformer including
a second primary winding connected between the first end of said second main switch and said load, anda second secondary winding connected between the first electrode of said second DC power supply and the second electrode of said second DC power supply, and magnetically coupled to said second primary winding, said first secondary winding and said first clamp diode connected in series between the first electrode of said first DC power supply and the second electrode of said first DC power supply, said second secondary winding and said second clamp diode connected in series between the first electrode of said second DC power supply and the second electrode of said second DC power supply, said first secondary winding and said first clamp diode connected in series, and said first primary winding and said second primary winding connected in series, and the connection node of said first primary winding and said secondary primary winding connected to said load. |
